Databases from CMS programs such as Medicare and Medicaid have tremendous potential utility for use in the conduct of experimental and non-experimental studies of the comparative drug effectiveness. When Medicare Part D begins to cover prescription drugs in 2006, this potential utility will be dramatically enhanced. A major limitation to the use of these databases, however, particularly since implementation of the HIPAA Privacy Rule, has been researchers' inability to obtain clinical records to verify study outcomes. Quality Improvement Organizations (QIOs) and Clinical Data Abstraction Centers (CDACs), under CMS contract, review charts from every non-federal short-stay hospital in the US that receives CMS payments. Given QIOs' and CDACs' mission of improving the quality of health care, together with their well-developed relationships with hospitals, a stable core of experienced chart abstractors, established infrastructure and procedures for assuring abstracting accuracy, and in-depth working knowledge of HIPAA regulations, they are potentially invaluable partners in studies of drug effectiveness in CMS beneficiaries. However, there is little experience verifying study outcomes under this model, and a number of important feasibility issues that need to be examined before it is known whether academic-QIO/CDAC partnerships are a viable option to verify clinical outcomes in studies using CMS data. Therefore, the University of Pennsylvania Center for Education and Research in Therapeutics (CERT) proposes a methodologic study to evaluate the feasibility of academic-QIO/CDAC partnerships to verify hospitalization study outcomes using clinical records. If successful, such a model will greatly improve the utility of CMS databases for research, which in turn will contribute enormously to clinical care and public health. [unreadable] [unreadable] [unreadable]